Sign reversal of the Hall effect in superconducting single crystals

Abstract

For detwinned Ni-doped single crystals of (Formula presented) with (Formula presented), we have measured the in-plane longitudinal and Hall resistivities. The residual resistivity (Formula presented) extrapolated from (Formula presented) above (Formula presented) increases with Ni concentration (Formula presented), indicating that the elastic scattering rate of conduction carriers (Formula presented) is increased. In the mixed state just below the superconducting transition temperature (Formula presented), a sign reversal of the Hall resistivity is observed. The in-plane Hall conductivity (Formula presented) is found to be the sum of two terms, (Formula presented) and (Formula presented). (Formula presented) and (Formula presented) are independent of field as in pure (Formula presented), but dependent on both temperature and Ni concentration. The temperature dependences of (Formula presented) and (Formula presented) weaken with increasing Ni concentration. © 1996 The American Physical Society.